A circle is placed in a square with a side length of 18 mm, as shown below. Find the area of the shaded region. Use the value 3.14 for it, and do not round your answer. Be sure to include the correct unit in your answer.

the shaded region = 69.66mm^2

Explanation:
Assume shaded region is X
Then :
X + Area of circle = area of square
X = area of square - area of circle

Find area of square:
Side length = 18mm
Area = 18 x 18 = 324

Find area of circle:
Side length of a square = the diameter of the circle = 18mm
And r(radius) = d/2 = 18/2 = 9
Area = pi x 9^2 = 254.34

Now find X
X = 324 - 254.34 = 69.66